i just dug out a distributor i bought from Rock Auto some time ago built by "World Performance".The slots are .410 (there is no advance stamping)... that should be around 10 or 11 x 2 for a total mechanical advance of about 20 - 22 degrees.This should let you run 12 - 14 initial and probably be O.K. right out of the box for all but the racers.
It only has one roll pin and no spring lock but a screw instead.The springs are heavy and light single stage but i don't know what the curve is.I ordered it for a '73 340 Challenger....model DST3890.No i don't have a Challenger...i just used that model for the order.
I haven't used it but it looks like a decent piece,hope this helps?
